It is known to effect the excavation of diaphragms, ditches, trenches, wells or other by means of excavation devices having two pairs of milling wheels with horizontal axes and substantially parallel during use to the excavation surface, which are driven by motor means. The motion is usually transferred to the shaft of the milling wheels by means of chain-type transmission means.
For example, diaphragms are usually deep perforations with a rectangular section, which are made in continuous manner in a vertical direction in the ground and have diverse functions, such as for example of a structural type, as in the perimeter walls of an underground building, as a foundation, as in surface buildings, or again with a water-proofing function, as in works on dams.
Normally, diaphragms are excavated by first making an excavation of two diaphragms, separate and substantially aligned, which are cast with concrete or plastic cement, and subsequently, by excavating a closing diaphragm which joins together said two cast diaphragms. In the last step, a part of each of the cast diaphragms is excavated by the excavation device, so as to guarantee the cleanliness of the surfaces that will be cast, and a good anchorage of the concrete or plastic cement.
However, with known excavation devices there may be a lack of accuracy in the excavation, which can thus reduce to below the design specifications both the continuity and the linearity of the diaphragms excavated.
Moreover, the forces to which the excavation device is subjected during the excavation can make the excavation devices rotate around the vertical during the excavation, accentuating the imprecision of the excavation. This renders the diaphragms made unsuitable to perform their structural function, their foundation function, and also their sealing function as described above.
A purpose of the present invention is to achieve an excavation device which allows to make the excavation with great precision of diaphragms, ditches, trenches, wells or other, with continuity and linearity in the disposition of the excavation.
Another purpose of the present invention is to achieve an excavation method which has great precision, and continuity and linearity in the disposition of the excavation.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.